The Jiongu could have a connection to Naruto's family that he was unaware of. Maybe it was something that his ancestors had encountered before. This discovery could change his perception of his family's history. Also, the Jiongu might seem like a great power at first, but it could turn out to be a double - edged sword. It could start to drain Naruto's life force or chakra over time, forcing him to find a way to either get rid of it or find a balance.
In the fanfic, if Naruto gets the Jiongu, it could have a huge impact on his relationships. His friends might be a bit wary of this new power at first. But Naruto being Naruto, he would probably find a way to show them that he's still the same person. He could use the Jiongu to protect them better, like creating barriers around them during battles. Also, it could be a factor in how his enemies view him. They might see him as an even greater threat and either target him more or try to avoid him altogether.
The sword might be a tool for Naruto to better understand his own heritage. For example, it could be linked to his Uzumaki clan in some way. He might discover that the sword was created by an Uzumaki ancestor to combat a specific threat that is now resurfacing. This would lead to Naruto delving deeper into his clan's history and unlocking new powers or techniques related to it. Also, the sword could attract unwanted attention from enemies who either fear its power or want it for themselves, forcing Naruto into new and dangerous battles.
One possible plot twist could be that Naruto gains the Mangekyou Sharingan in a moment of extreme emotional turmoil, like seeing Sasuke in a life - threatening situation. This new power might make him an outcast in Konoha at first, as the Sharingan is a symbol of the Uchiha. Another twist could be that the Mangekyou Sharingan has some unforeseen side effects on Naruto's chakra system, making it difficult for him to control his normal jutsu. It could also lead to a power struggle within the village as some might fear Naruto's new - found power.
One interesting plot twist could be that the alternate Naruto is from a parallel universe where the roles of good and evil are reversed. This would force the real Naruto to question his own beliefs and values. And it might also lead to a battle between the two Narutos, not just a friendly encounter, as they fight over what is right and wrong.
Well, it could start with Mizuki having some sort of relationship with Fem Naruto. Maybe Mizuki has an ulterior motive in getting close to her. Then, through some events, Fem Naruto becomes pregnant. It could lead to a lot of drama, like how they deal with the situation in a world where Naruto is a female and pregnant with Mizuki's child. There would likely be reactions from their friends and foes alike.
Another plot twist might be that Sasuke discovers a hidden enemy who is targeting their unborn child. This could lead to Sasuke having to go on a dangerous mission while Sakura is pregnant to protect their family. It would add a lot of tension to the story as Sakura is left at home worried about him.
One exciting plot twist could be that Naruto's new bloodline gives him the ability to control time. He could then use this power to go back and prevent some of the tragedies in the Naruto world, like the Uchiha massacre. Another possibility is that the bloodline makes him immune to all genjutsu, which would completely change his battles against opponents like Itachi or Madara.
A plot twist could be that Medusa is actually an undercover agent sent to the Naruto world to steal secrets, but she falls in love with Naruto instead. This would create a conflict between her original mission and her new - found feelings.
A possible plot twist in this fanfiction might be that Naruto's new status as the jinchuriki of Saiken attracts a new group of enemies who are specifically after the power of the Six - Tails. Also, there could be a situation where Naruto's friends start to fear him because of Saiken's power, thinking he might lose control. And perhaps there is a hidden prophecy that only Naruto as the jinchuriki of Saiken can fulfill, which leads to a whole new adventure and set of challenges for him.
A potential plot twist could be that Zabuza has a hidden agenda for allowing Naruto to join him. Maybe he plans to use Naruto as a pawn against the Hidden Leaf Village, which would create a huge moral dilemma for Naruto.